Drill - Tap Combo Tools

[dws35]

My engineer is looking to use HSS drill - tap combo tools for a production job. Here are parameters.

Lot size is 300 pcs, ordered 1 or twice per month.
Material is casting, ductile iron, 80-55-06 BHN 187-255.
Hole sizes are .375-16, .500-13, and .750-14 NPSF.
All hole depths are 1 to 1.5 times diameter.
The .375-16 hole starts on an inclined surface with a 10 - 15 degree angle.
Hole count is 3 of each size.

I am concerned that these tools are more suited for short run, tool room, maintenance use, more so than for long term production use.

Any thoughts on these tools?

Thx

[RevEdo]

Au contrair. Draps, as we call them, came out of necessity in the high volume production end of machining. You see, when you are making millions of parts, the tool change time of just 1 tool (changing a tool on a mill, or indexing the turret on a lathe) can mean the diff tween profit and loss.

[RICHARD ZASTROW]

Those tools (Draps) work well when the drill is through the work before the tap is engaged. The speed and feed rate of the tap section are usually quite different than the drilling speed and feed rates.

They are especially effective on thin plate or sheet metal parts.

Dick Z

[dws35]

My concern the speeds / feeds will have to be much lower with HSS tools as compared to coated carbide drills / premium HSS taps with thru coolant on them. Also, I figure that these tools are going to last thousands of holes.

Tool change is not really an issue, as index time from station to station is about .5 second. As noted, we are making a few hundred parts, not millions.

Does my logic make any sense?

Thx